MU2 certification support (smoking and clinical terms), final revision.

-Support for MU2 requirements for smoking status
-Support for broad SNOMED clinical terms
-A new code type was added to support this
-Support for Clinical Term Code(s) mapping in Administration->Lists
-Added ability to import the SNOMED US extension pack
-The size of the code columns in codes table was increased to
support these longer SNOMED codes.